On the fishery, biology and the hatchery technology of the portunid crab Portunus pelagicus (TH 099)

Josileen, Jose
(2001)
On the fishery, biology and the hatchery technology of the portunid crab Portunus pelagicus (TH 099).
["eprint_fieldopt_thesis_type_phd" not defined] thesis, Cochin University of Science and Technology, Cochin.

Abstract

Crabs belonging to more than 4500 extant species of decapod crustaceans are
included in the infraorder Brachyura. The brachyura show extreme versatility in
distribution. They are found in all climates, and in terrestrial, semi terrestrial and
from the shore to deep sea, in marine, brackish as well as freshwater environments.
Although earlier surveys have recorded above 640 species of crabs from Indian
waters, only eight species are commonly referred to as 'edible crabs' inhabiting the
coastal waters and adjoining brackishwater environment and support localised and
sustenance fishery to some extent. Crabs are members of Crustacea, a class of
invertebrate phylum Arthropoda that includes the animals with jointed legs and a
hardened outer covering or exoskeleton. Crab belong to the order Decapoda a name
which refers to this fact that the members of this order have 5 pairs of legs. The true
crabs are placed in the suborder Brachyura an appropriate name for this group, as
their shortened flap-like abdomen or tail is folded under the body CRees, 1963). The
presently studied crab Portunus (Portunus) pelagicus, is a marine species belongs to
the family Portunidae and subfamily Portuninae. Although the latest nomenclature of
the crab is Portllnus (Portunus) pelagicus (Linnaeus), for the sake of brevity,
' Portllnus pelagicus' is used throughout the text.
In the Indian Ocean, the crab fauna of Portunidae family is included under
sub families, PodoPhthaimidae (Borradaile), Catoptrinae (Sakai), Portuninae
(Rafinesque), Caphyrinae (Alcock), Carcininae (Macleay) and Polybiinae (Ortmann).
Most of the edible crabs caught from marine and brackishwater environments belong
to the sub family Portuninae. In the seas around India, five genera of Portuninae have
been reported by various authors. They are Scylla, Por/unlls, Charybdis, Lupocyc/us
and Thalamita. Among them the first three genera contribute to the commercial crab
fishery.
The richness, variety and fishery of marine crabs of Indian seas have been
investigated by many workers over the past 100 years. Among them the notable
works are of Alcock (1895,1896,1898-1900), de Man (1908), Kemp (1915,1919a,b),
Chopra ( 1931 , 1939), Prasad and Tampi (1951, 1953), Menon (1952), Jones and
Sujansingani (1952), Chhapgar (1957,1962), Sankarankutty (196Ia, b,1965), George
and Nayak (1961), Ramamurthy (1972), Prasad and Nair (1973), Rao el al. (1973),
Dhawan el al. (1976) and Kurup el al. (1990).